Rust

"Rust

Rust is an iron oxide, a usually red oxide formed by the redox reaction of iron and oxygen in the presence of water or air moisture. Several forms of rust are distinguishable both visually and by spectroscopy, and form under different circumstances. Rust consists of hydrated iron(III) oxides Fe₂O₃.nH₂O and iron(III) oxide-hydroxide (FeO(OH), Fe(OH)₃).

Prevention

Coatings and painting Rust formation can be controlled with coatings, such as paint, lacquer, varnish, or wax tapes that isolate the iron from the environment."

Wikipedia, Rust, 2019

To prevent rust you have to block the oxygen or water. One of the used methods is to coat the iron. This was known recently, however this was portrayed in the Quran 1400 years before it was discovered. In the story of Thu-Al-Karnain he poured tar over the iron.